Prediction of body-fat percentage from skinfold and bio-impedance measurements in Indian school children

Abstract

Background/Objectives: Few equations for calculating body-fat percentage (BF%) from field methods have been developed in South-Asian children. The objective of this study was to assess agreement between BF% derived from primary reference methods and that from skinfold equations and bio-impedance analysis (BIA) in Indian children. Subjects/Methods: We measured BF% in two groups of Indian children. In Pune, 570 rural children aged 6-8 years underwent dual-energy X-ray absorptiometry (DXA) scans. In Mysore 18 O in doubly labeled water was administered to 59 urban children aged 7-9 years. We conducted BIA at 50 kHz and anthropometry, including sub-scapular and triceps skinfold thicknesses. We used the published equations of Wickramasinghe, Shaikh, Slaughter and Dezenburg to calculate BF% from anthropometric data and the manufacturer's equation for BIA measurements. We assessed agreement with values derived from DXA and doubly labeled water using Bland-Altman analysis. Results: Children were light and thin on average compared with international standards. There was poor agreement between the reference BF% values and those from all equations. Assumptions for Bland-Altman analysis were not met for Wickramasinghe, Shaikh and Slaughter equations. The Dezenberg equations under-predicted BF% for most children (mean difference in Pune 13.4, LOA 22.7, 4.0 and in Mysore 7.9, LOA (-13.7 and-2.2). The mean bias for the BIA equation in Pune was +5.0% and in Mysore +1.95%, and the limits of agreement were wide;-5.0, 15.0 and-7.8, 11.7 respectively.Conclusions:Currently available skinfold equations do not accurately predict BF% in Indian children. We recommend development of BIA equations in this population using a four-compartment model. © 2011 Macmillan Publishers Limited All rights reserved.